Igneous VM

Virtual Microscope teaching sets provided by University College Dublin :
THIN SECTION: A1.04
Type: Igneous
Category: Two-mica granite
Place: Northern pluton of the Leinster granite, Co. Dublin.
Age: Devonian
  • Rotation point 1: anhedral kaolinized microcline overgrowing zoned subhedral sericitised plagioclase and subhedral biotite.
  • Rotation point 2: biotite with pleochroic haloes partially chloritized along cleavages.
 Open Virtual Microscope

GE-LAB
THIN SECTION: A8.27
Type: Igneous
Category: Granophyre (microgranite)
Place: Mourne Granite, Co. Down
Age: Paleogene
  • Rotation point 1: slightly kaolinized twinned perthitic orthoclase in graphic intergrowth with quartz.
    Rotation point 2: brown biotite with thin outer blue-green zone.
 Open Virtual Microscope

GE-LAB
THIN SECTION: A10.13
Type: Igneous
Category: Pyroxene Andesite
Place: Hungary
Age: ?
  • Rotation point 1: two intergrown zoned twinned euhedral augite phenocrysts (better to have rotation with larger field of view if possible, maybe ~8-10 mm, to get full crystals).
  • Rotation point 2: two intergrown augite phenocrysts, one twinned, the other an approximately acute bisectrix section showing 90 degree cleavages and octagonal habit.
 Open Virtual Microscope

GE-LAB
THIN SECTION: 11.588
Type: Igneous
Category: Magnetite gabbro
Place: Bushveld, South Africa.
Age: Precambrian
  • Rotation point 1: pigeonite inverted to orthopyroxene with two generations of exsolved augite lamellae.
  • Rotation point 2: augite with very fine lamellae of exsolved orthopyroxene.
 Open Virtual Microscope

GE-LAB

Developing Digital Teaching & Learning Resources for the Virtual Microscope